There's an old football saying that's goes something like this: "Three things can happen when you throw the ball and two of them are bad." If you're not a football fan, you may not understand this as a metaphor for convertibles, but suffice it to say that cutting the roof off a coupe and replacing it with a folding canvas contraption opens a veritable Pandora's box. The roof can leak. The body can rattle. Terms like "fit and finish" and "noise, vibration, and harshness" have a tendency to become pejorative. But just as coaches still call pass plays, automakers still build convertibles. Because when everything goes right, there's nothing more exciting than cruising around with the top down (football excepted).

I survey the small warehouse-like plant in Kitchener, Ontario, where ASC Inc. is turningToyota Camry Solara coupes into ragtops. From where I'm standing I can see the entire operation spread out in front of me, from the roar of the Sawzall tearing into steel to the downpour of the water test station. When it was explained to me in the conference room, the process seemed pretty simple: start with a coupe, cut off its top, weld in structural reinforcements, add a convertible top, and tie up the loose ends on the interior. Voilá, summer fun.

But now that I've stepped out onto the floor with my tour-guide-for-the-day, the guy who actually makes this "simple" process happen, every day, my initial impression is more along the lines of: "Convertibles are a royal pain in the $*! to build..."

Interrupting my thought, this guy—plant manager Don Kushmaul—tugs at my arm. He wants to show me the fixtures that his people are using to assemble the top. He tells me that this Solara top, with its "floating five-bow," is the most sophisticated design that ASC has ever used. He should know, as it was this project that brought him back from California, where he had been managing the ASC facility that had built Celica convertibles for Toyota since 1983.

More than just building a new top, this new plant is, as Kushmaul describes it, fundamental to "the evolution of the relationship" between ASC and Toyota. In fact, ASC is working for an entirely different part of Toyota, with an entirely different philosophy. This begets a different, two-stage process for this chop shop, which means that Kushmaul et al. are learning just how challenging simplicity can really be.

As you might expect from a Midwesterner-turned-Californian who's now doing the bidding of a Japanese company located in Canada, Don Kushmaul has a rather different attitude toward his life and work than most. I ask him if he regrets having to move away from sunny SoCal. He replies: "I didn't like living out there for a long time. Then about the time I started to like it, I came back."

Perhaps I'm reading too much into a mere statement of fact, but there is a certain temperament that's necessary to deal with a Japanese manufacturing company, something that Kushmaul had not done prior to his move to Ontario. See, when he was in California, he used to get those Celicas directly from Toyota in Japan. They'd come off the boat as coupes and his crew would do their magic Transformer act, turning ready-for-sale coupes into ready-for-sale convertibles. ASC's customer for these vehicles was actually Toyota Motor Sales USA Inc. (TMS), a very American company (think of customers jumping up in the air and shouting, "I love what you do for me..."). Point being, TMS didn't particularly care how ASC was making these cars, just that it did it and did it good. Which, by most assessments, it did. But then the Celica convertible was discontinued...but that's another story entirely.

This color-coded body shows additional reinforcements added by ASC in yellow. Red parts are added in the TMMC body shop.

When it was decided that ASC would get the contract to build the annual run of 6,000 Solara convertibles, it was also decided that they would do it in a new facility about 15 km from Cambridge, Ontario, where the Solara coupes are made at Toyota Motor Manufacturing Canada Inc. (TMMC). TMMC, of course, has a decidedly different outlook on building cars than TMS. As Kushmaul says, "They have kind of taken us to school, so to speak, helping ASC take the next step in manufacturing."

This "next step" involves making the process more efficient by reducing the waste inherent in cutting up a complete car. To this end, a coupe body that is destined to become a convertible actually begins its transformation in the TMMC body shop, where the first of many structural reinforcements are added. But rather than heading from body shop to paint shop, it gets wheeled off the TMMC line on a dolly and into the back of an 18-wheel freight hauler, the trailer of which has been modified with a track down its center. No fancy material handling system here, just a simple and inexpensive modification to existing equipment that allows one semi to carry three coupe bodies to ASC, and three convertible bodies upon its return.

The coupe body remains on this same dolly as it is manually wheeled through the ASC body shop, where it gets attached to fixtures so that more reinforcements can be welded in and the roof can be cut off. Of note is the fact that ASC is now fixturing the bodies off the door opening rather than the B-pillar, resulting in better fit and finish by decreasing the number of adjustments that need to be made to get the doors and windows to fit snugly. This is just one of many error-proofing techniques that were developed with Toyota's assistance.

About 95% of the welding is done with manual MIG welders, while the remaining 5-7% is spot welded; cutting is done with a conventional Sawzall, as well as a plasma cutter. This labor-intensive procedure means that the operators must have good mechanical skills and impressive dexterity. Additionally, they need to be smart, because each operator has a cycle time that lasts approximately 30 minutes. To the process engineers at Toyota this is far longer than usual, yet they still applied their method of standardizing each individual operator movement. Because of this minute choreography, considerable cycle time improvements have been made since ASC launched last spring. But not without a price. Kushmaul is candid in admitting that the work instructions are complex (imagine remembering a 30-minute sequence of motions yourself), so much so that some of his original operators just couldn't hack it.

That orange thing is the dolly that's used to ferry the body from TMMC to ASC, down the ASC line, and back to Cambridge.

Once a body is completed, it is wheeled back on the trailer and taken back to TMMC for a just-in-time run through the paint booth. This is the most aggressive JIT manufacturing arrangement that ASC has ever participated in, as Toyota leaves no leeway in its schedule. For every coupe body pulled out to send to ASC, there must be a convertible body ready to take its place on the way to paint. Furthermore, there is no room in ASC's plant to stockpile bodies (or completed cars for that matter), just a marked off area in front of the loading dock that acts as a kanban; it holds only enough bodies to fill the next trailer.

After arriving at TMMC, a convertible body is e-coated and painted, then goes through final assembly along with the coupes. One of the key benefits cited in switching to this two-stage process is that each convertible emerges from the paint shop with the same corrosion protection as a coupe.

Once assembly is complete, the convertibles roll off the end of the line at TMMC missing only airbags and their ASC-installed gear, some of which is in the backseat and some of which is waiting for the cars in Kitchener. The almost-complete cars are driven onto the same semi-trailers and hauled back for their second go around with Kushmaul and company. And just like the bodies, for every three that get unloaded from each trailer, three more totally complete cars get loaded up to head back to TMMC for airbag fitting and shipping prep.

Like the body shop, ASC's assembly line is a semicircle; however this line is dominated by two water test booths. After the convertible top gets attached (it's built up as a subassembly beside the line), the car gets driven through one of the two booths where it is subjected to a Noah-scale downpour. Then a very critical operator inspects the moldings for dampness. Even the slightest hint of moisture means the top gets adjusted. ASC is exceptionally proud of its 100% leak-free standards. So much so that once the rest of the interior gets installed, the car goes through another slightly less intense downpour to make sure that the rest of the interior assembly didn't compromise the fit of the top. While Kushmaul explains that these testers are necessary to prevent defective cars from getting further down the line (like, say, all the way to a Toyota dealership), he admits that they would love to get good enough at the process to be able to eliminate them. At least that's what the Toyota guys are pushing for.

The Solara convertible as it arrives from TMMC, before going through the second stage of assembly. That gear in the backseat is material that's shipped over from Toyota in the car—even more efficient than returnable donnage.

It's important to mention that standardized work was developed for the assembly line, just as it was for the body shop. I spot one clever process improvement that must have resulted from careful scrutiny of operator movements. Rather than installing both rocker moldings at the same time, as my gaijin mind would think logical, each one is installed separately. An operator working on the right side of the vehicle installs the right rocker molding early on in the assembly process. This operator has many other tasks to complete, but because he's already in the correct position, he can install the rocker molding without increasing his cycle time by more than a few seconds. The car will then move nearly all the way to the end of the line, going through many other assembly stages, before an operator whose tasks position him on the left side of the car will attach the left rocker molding. It's this way of rationalizing each and every operator action, truly putting the operator's needs first, that leads to the kinds of cycle time reductions that make continuous improvement a reality.

The focus on process and attention to detail extends well beyond the operator. As Kushmaul says, "Toyota manages every single event, from the first contact with the supplier to the time the car goes on the truck. They manage every single element in that chain of events." Besides just helping ASC with the manufacturing side of lean, working with Toyota suppliers has also been a good experience for ASC as a corporation. All of which adds up to a better product and a more productive plant.

About a month after my visit, I am cruising through suburban Detroit on a beautiful summer day behind the wheel of a Solara convertible that I've borrowed from Toyota. The wind blows gently through my hair and the sun warms the back of my neck.

Then it comes to me; I finally complete that initial thought that Kushmaul had interrupted.